Dissolved organic matter (DOM) isolated from the leachates with different landfill ages was fractionated into hydrophobic acid (HOA), hydrophobic neutral (HON), hydrophobic base (HOB) fractions and hydrophilic matter (HIM) based on hydrophobicity, and the composition and degradation potential of the bulk DOM and its fractions were investigated by excitation-emission matrix fluorescence spectra coupled with parallel factor analysis. Results showed that the bulk DOM comprised fulvic-, humic-, tryptophan- and tyrosine-like substances, as well as component C1, whose composition and origin was unidentified. Landfill process increased the content of component C1, fulvic- and humic-like matter. The HON fractions comprised primarily component C1 and tyrosine-like matter. The HOA, HOB and HIM fractions isolated from the young leachates consisted mainly of tryptophan- and tyrosine-like substances. As to the intermediate and old leachates, the HOA and HOB fractions comprised mainly component C1, while the HIM comprised mainly fulvic-like matter. The HIM showed the most resistant against biodegradation among the four fractions, and was the main component of leachate treatment. Advanced oxidation and/or membrane treatment are recommended to remove the HIM fraction due to its hydrophilic and stable characteristics.
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http://dx.doi.org/10.1016/j.chemosphere.2015.08.071 | DOI Listing |
Pathogens
March 2024
Infectious Diseases and Chemotherapy Research Laboratory, First Department of Pediatrics, Medical School, "Aghia Sophia" Children's Hospital, National and Kapodistrian University of Athens, 11527 Athens, Greece.
Sequencing of the T-cell repertoire is an innovative method to assess the cellular responses after immunization. The purpose of this study was to compare T-cell repertoires after COVID-19 immunization with homologous (HOB) and heterologous (HEB) boosting. The study included 20 participants with a median age of 27.
View Article and Find Full Text PDFEcotoxicol Environ Saf
January 2024
Consortium on Health, Environment, Education, and Research (CHEER), Department of Science and Environmental Studies, The Education University of Hong Kong, Tai Po, Hong Kong Special Administrative Region of China.
To understand the mechanism of dark abiotic mercury (Hg) methylation by algae-derived dissolved organic matter (DOM) and effectively manage the environmental risks of mercury methylation in aquaculture areas, we investigated the influence of subfractions of DOM released from algae (Ulothrix sp.) decomposition on mercury methylation. The results showed that the hydrophobic basic component (HOB) in DOM exhibited the most substantial promotion effect on Hg methylation.
View Article and Find Full Text PDFCrit Care Explor
December 2023
Division of Pulmonary, Critical Care, Sleep Medicine, and Physiology, University of California San Diego, La Jolla, CA.
In some patients with acute respiratory distress syndrome (ARDS), a paradoxical improvement in respiratory system compliance (C) has been observed when assuming a supine (head of bed [HOB] 0°) compared with semirecumbent (HOB 35-40°) posture. We sought to test the hypothesis that mechanically ventilated patients with ARDS would have improved C, due to changes in ventilation distribution, when moving from the semirecumbent to supine position. We conducted a prospective, observational ICU study including 14 mechanically ventilated patients with ARDS.
View Article and Find Full Text PDFFEMS Microbiol Ecol
November 2023
Institut national de la recherche scientifique, Centre Armand-Frappier Santé Biotechnologie, 531 boulevard des Prairies, Laval, Québec H7V 1B7, Canada.
High-affinity H2-oxidizing bacteria (HA-HOB) thriving in soil are responsible for the most important sink of atmospheric H2. Their activity increases with soil organic carbon content, but the incidence of different carbohydrate fractions on the process has received little attention. Here we tested the hypothesis that carbon amendments impact HA-HOB activity and diversity differentially depending on their recalcitrance and their concentration.
View Article and Find Full Text PDFSci Total Environ
January 2024
Water Resources and Environmental Institute, Xiamen University of Technology, Xiamen 361005, China.
Frequent extreme precipitation events due to global warming can lead to large amounts of pollutants entering source water bodies via surface runoff and wet deposition, thus posing a threat to water supply security. In order to better understand the source characteristics and leaching mechanisms of rainwater dissolved organic matter (DOM), as well as its disinfection by-products formation potential (DBPsFP) during disinfection processes, rainwater samples were collected and extracting experiments were conducted. Three components were identified in rainwater through Parallel factor (PARAFAC) analysis, which were microbial humic-like component C1 (63.
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